package com.cjj.calculatordemo;

import android.R.integer;
import android.app.Activity;
import android.os.Bundle;
import android.provider.Settings;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;

import java.math.BigDecimal;

public class MainActivity extends Activity implements OnClickListener {
	Button btn_0, btn_1, btn_2, btn_3, btn_4, btn_5, btn_6, btn_7, btn_8, btn_9;
	Button btn_point;
	Button btn_clear;
	Button btn_del;
	Button btn_plus;
	Button btn_minus;
	Button btn_multiply;
	Button btn_divide;
	Button btn_equal;
	EditText et_input;
	boolean clear_flag;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		btn_0 = (Button) findViewById(R.id.btn_0);
		btn_1 = (Button) findViewById(R.id.btn_1);
		btn_2 = (Button) findViewById(R.id.btn_2);
		btn_3 = (Button) findViewById(R.id.btn_3);
		btn_4 = (Button) findViewById(R.id.btn_4);
		btn_5 = (Button) findViewById(R.id.btn_5);
		btn_6 = (Button) findViewById(R.id.btn_6);
		btn_7 = (Button) findViewById(R.id.btn_7);
		btn_8 = (Button) findViewById(R.id.btn_8);
		btn_9 = (Button) findViewById(R.id.btn_9);
		btn_point = (Button) findViewById(R.id.btn_point);
		btn_clear = (Button) findViewById(R.id.btn_clear);
		btn_del = (Button) findViewById(R.id.btn_del);
		btn_plus = (Button) findViewById(R.id.btn_plus);
		btn_minus = (Button) findViewById(R.id.btn_minus);
		btn_multiply = (Button) findViewById(R.id.btn_multiply);
		btn_divide = (Button) findViewById(R.id.btn_divide);
		btn_equal = (Button) findViewById(R.id.btn_equal);
		
		et_input = (EditText) findViewById(R.id.et_input);

		btn_0.setOnClickListener(this);
		btn_1.setOnClickListener(this);
		btn_2.setOnClickListener(this);
		btn_3.setOnClickListener(this);
		btn_4.setOnClickListener(this);
		btn_5.setOnClickListener(this);
		btn_6.setOnClickListener(this);
		btn_7.setOnClickListener(this);
		btn_8.setOnClickListener(this);
		btn_9.setOnClickListener(this);
		btn_point.setOnClickListener(this);
		btn_clear.setOnClickListener(this);
		btn_del.setOnClickListener(this);
		btn_plus.setOnClickListener(this);
		btn_minus.setOnClickListener(this);
		btn_multiply.setOnClickListener(this);
		btn_divide.setOnClickListener(this);
		btn_equal.setOnClickListener(this);
		
	}

	@Override
	public void onClick(View v) {
		// TODO Auto-generated method stub
		String str = et_input.getText().toString();
		switch (v.getId()) {
			case R.id.btn_0:
			case R.id.btn_1:
			case R.id.btn_2:
			case R.id.btn_3:
			case R.id.btn_4:
			case R.id.btn_5:
			case R.id.btn_6:
			case R.id.btn_7:
			case R.id.btn_8:
			case R.id.btn_9:
			case R.id.btn_point:
				if (clear_flag) {
					clear_flag = false;
					str = "";
					et_input.setText("");
				}
				et_input.setText(str + ((Button) v).getText());
				break;
			case R.id.btn_plus:
			case R.id.btn_minus:
			case R.id.btn_multiply:
			case R.id.btn_divide:
				if (clear_flag) {
					clear_flag = false;
					str = "";
					et_input.setText("");
				}
				et_input.setText(str + " " + ((Button) v).getText() + " ");
				break;
			case R.id.btn_del:
				if (clear_flag) {
					clear_flag = false;
					str = "";
					et_input.setText("");
				} else if (str != null && !str.equals("")) {
					et_input.setText(str.substring(0, str.length() - 1));
				}
				break;
			case R.id.btn_clear:
				clear_flag = false;
				str = "";
				et_input.setText("");
				break;
			case R.id.btn_equal:
				getResult();
				break;
			default:
				break;
		}
	}

	
	private void getResult() {
		String exp = et_input.getText().toString();
		if (exp == null || exp.equals("")) {
			return;
		}
		if (!exp.contains(" ")) {
			return;
		}
		if (clear_flag) {
			clear_flag = false;
			return;
		}
		clear_flag = true;
		double result = 0;

		String s1 = exp.substring(0, exp.indexOf(" "));
        Log.i("exp", s1);
        String op = exp.substring(exp.indexOf(" ") + 1, exp.indexOf(" ") + 2);
        Log.i("exp", op);
        String s2 = exp.substring(exp.indexOf(" ") + 3);
        Log.i("exp", s2);

        switch (op) {
            case "+":
                float plus = Float.parseFloat(s1) + Float.parseFloat(s2);
                et_input.setText(String.valueOf(plus));
                break;

            case "-":
                BigDecimal b1 = new BigDecimal(Float.parseFloat(s1));
                BigDecimal b2 = new BigDecimal(Float.parseFloat(s2));
                float minus = (float) (Math.round((b1.subtract(b2).floatValue()) * 100) / 100.0);
                et_input.setText(String.valueOf(minus));
                break;

            case "*":
                float multiply = Float.parseFloat(s1) * Float.parseFloat(s2);
                et_input.setText(String.valueOf(multiply));
                break;

            case "/":
                float divide = Float.parseFloat(s1) / Float.parseFloat(s2);
                et_input.setText(String.valueOf(divide));
                break;

            default:
                break;
        }

	}
}
